A new Request for Comments is now available in online RFC libraries. RFC 3327 Title: Session Initiation Protocol (SIP) Extension Header Field for Registering Non-Adjacent Contacts Author(s): D. Willis, B. Hoeneisen Status: Standards Track Date: December 2002 Mailbox: email@example.com, firstname.lastname@example.org, email@example.com Pages: 17 Characters: 36493 Updates/Obsoletes/SeeAlso: None I-D Tag: draft-willis-sip-path-08.txt URL: ftp://ftp.rfc-editor.org/in-notes/rfc3327.txt The REGISTER function is used in a Session Initiation Protocol (SIP) system primarily to associate a temporary contact address with an address-of-record. This contact is generally in the form of a Uniform Resource Identifier (URI), such as Contact: <sip:firstname.lastname@example.org> and is generally dynamic and associated with the IP address or hostname of the SIP User Agent (UA). The problem is that network topology may have one or more SIP proxies between the UA and the registrar, such that any request traveling from the user's home network to the registered UA must traverse these proxies. The REGISTER method does not give us a mechanism to discover and record this sequence of proxies in the registrar for future use. This document defines an extension header field, "Path" which provides such a mechanism. This document is a product of the Session Initiation Protocol and the Session Initiation Proposal Investigation Working Groups of the IETF. This is now a Proposed Standard Protocol. This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited. This announcement is sent to the IETF list and the RFC-DIST list. Requests to be added to or deleted from the IETF distribution list should be sent to IETF-REQUEST@IETF.ORG. Requests to be added to or deleted from the RFC-DIST distribution list should be sent to RFC-DIST-REQUEST@RFC-EDITOR.ORG. Details on obtaining RFCs via FTP or EMAIL may be obtained by sending an EMAIL message to rfc-info@RFC-EDITOR.ORG with the message body help: ways_to_get_rfcs. For example: To: rfc-info@RFC-EDITOR.ORG Subject: getting rfcs help: ways_to_get_rfcs Requests for special distribution should be addressed to either the author of the RFC in question, or to RFC-Manager@RFC-EDITOR.ORG. Unless specifically noted otherwise on the RFC itself, all RFCs are for unlimited distribution.echo Submissions for Requests for Comments should be sent to RFC-EDITOR@RFC-EDITOR.ORG. Please consult RFC 2223, Instructions to RFC Authors, for further information.